With a 2-1 victory over Lynbrook High School, the MacArthur High School Generals capped their 2019 baseball season with the 37th conference championship in their history, this year in A-1. McArthur racked up an impressive 10-4-1 record in conference play, and an overall record of 11-7-1.

Guiding the Generals’ effort, head coach Steve Costello reached a milestone of his own, notching his 500th career victory in a 4-3 squeaker over Herricks High and finishing the season with 504 wins.

Costello, 59, who wears a second hat as director of social studies and world language arts for the Levittown School District, gave the credit for his success to his players. Coaching is more a matter of luck than skill, he said modestly. “You have to coach at a strong baseball school,” he said. “After that, you just keep going. It’s not really that much my accomplishment.”

Costello has certainly kept going. The high school baseball season has 19 regular games. With the postseason, a team may play as many as 29 games. Costello has averaged nearly 19 wins in each of his 27 seasons, including five trips to the state championships. In 1994 — his second season as head coach — the Generals went undefeated and won the state title, the only Long Island team ever to accomplish that feat.

Over the years, Costello has coached a number of standout players, including Jeff Tyler, an All-American at Adelphi University; Randy Leek, an outstanding minor league player who finished his career with the Long Island Ducks; and Frankie Vanderka, who helped the 2013 Stony Brook Seawolves make it to the College World Series after hurling a three-hitter against perennial baseball behemoth Louisiana State University.

Costello stressed the importance of relationships over sports statistics. “It’s not only their baseball accomplishments that are important,” he said of his players.

A 1977 Levittown Memorial High School graduate, Costello played catcher, second base and outfield for the Panthers, but was known mainly as a slugger. He did not continue his playing career at the University of Albany. “It wasn’t as common in those days to play in college,” he said. “Most players finished their sports careers at the high school level.”

These days, he said, “Kids understand at an earlier age that they’re going to be on their own, responsible for their own success. They’re more focused, more driven than kids in my generation were — more self-directed.” In addition, athletes have many more opportunities to play college sports.

Costello chaired MacArthur’s social studies department for a dozen years before assuming his current districtwide role. His area of academic interest is European history from 1450 to the present, he said. It is a period of outsized personalities — the Borgias, Henry VIII, Louis XIV and Napoleon — the last of whom Costello laughingly credited for his coaching philosophy. “Never interrupt your enemy when he is making a mistake,” the French emperor was alleged to have said.

As to whether Costello considers himself a Napoleon of the baseball diamond, he laughed and said he was both taller and less egotistical. But high school baseball does tend to be a strategic game, he added, given the paucity of power hitting.

“Pitching is the key,” he said, and MacArthur has been fortunate in that respect. The Generals have won the Diamond Award, given to the top pitching staff among Long Island’s 56 high school teams, 10 times during Costello’s tenure, including six wins in the past 11 years.

Another key to his squads’ success has been his concern for his players’ health. “Up until a few years ago, we were in a cycle of one-sport athletes,” he said. The result was the kind of repetitive stress injuries more commonly seen in end-of-career professionals.

“We insist players don’t play in November and December,” between seasons, Costello said. “The ones who listen, we can keep healthy.” Inevitably, though, some go their own way, although Costello says it has become less common in the past half-dozen years or so.

“The real culprits are the private trainers,” he said. Some players and their parents, looking toward or professional careers, seek out private coaches who don’t necessarily have the players’ best interests in mind.

Costello is something of a contrarian in the baseball community, believing that natural talent is a far greater determinant in predicting sports success than a player’s work ethic. He pointed to the example of former Mets and Yankees great Darryl Strawberry, who “maybe didn’t have the greatest work ethic,” but whose athletic gifts were so prodigious that he helped his teams to four World Series championships.

Costello is more a fan of the game than of any one team — except his own, of course. He did allow that as a former Mets fan, “I loathed the Yankees.” But, he added, “I don’t really follow any particular team. I like a good high school or college game. If I’m flipping through the channels and come across a college baseball game, I’m very happy.”